Add ability to skip yaml loading

Added a flag, 'load_yaml_config' that defaults to True.
If set to false, no clouds.yaml files will be loaded. This
is beneficial if os-client-config wants to be used inside of
a service where end-user clouds.yaml files would  make things
more confusing.

Change-Id: Idbc82bb931e9edf1bbcc575237c0e202e219c218

os_client_config/__init__.py

@@ -24,7 +24,8 @@ __version__ = pbr.version.VersionInfo('os_client_config').version_string()
 
 
 def get_config(service_key=None, options=None, **kwargs):
-    config = OpenStackConfig()
+    load_yaml_config = kwargs.pop('load_yaml_config', True)
+    config = OpenStackConfig(load_yaml_config=load_yaml_config)
     if options:
         config.register_argparse_arguments(options, sys.argv, service_key)
         parsed_options = options.parse_known_args(sys.argv)

os_client_config/config.py

@@ -173,13 +173,19 @@ class OpenStackConfig(object):
     def __init__(self, config_files=None, vendor_files=None,
                  override_defaults=None, force_ipv4=None,
                  envvar_prefix=None, secure_files=None,
-                 pw_func=None, session_constructor=None):
+                 pw_func=None, session_constructor=None,
+                 load_yaml_config=True):
         self.log = _log.setup_logging(__name__)
         self._session_constructor = session_constructor
 
-        self._config_files = config_files or CONFIG_FILES
-        self._secure_files = secure_files or SECURE_FILES
-        self._vendor_files = vendor_files or VENDOR_FILES
+        if load_yaml_config:
+            self._config_files = config_files or CONFIG_FILES
+            self._secure_files = secure_files or SECURE_FILES
+            self._vendor_files = vendor_files or VENDOR_FILES
+        else:
+            self._config_files = []
+            self._secure_files = []
+            self._vendor_files = []
 
         config_file_override = os.environ.pop('OS_CLIENT_CONFIG_FILE', None)
         if config_file_override:

os_client_config/tests/test_config.py

@@ -16,6 +16,7 @@ import argparse
 import copy
 import os
 
+import extras
 import fixtures
 import testtools
 import yaml
@@ -577,6 +578,37 @@ class TestConfigArgparse(base.TestCase):
         self.assertEqual(cc.region_name, 'region2')
         self.assertEqual('my-network', cc.config['external_network'])
 
+    def test_get_one_cloud_no_yaml_no_cloud(self):
+        c = config.OpenStackConfig(load_yaml_config=False)
+
+        self.assertRaises(
+            exceptions.OpenStackConfigException,
+            c.get_one_cloud,
+            cloud='_test_cloud_regions', region_name='region2', argparse=None)
+
+    def test_get_one_cloud_no_yaml(self):
+        c = config.OpenStackConfig(load_yaml_config=False)
+
+        cc = c.get_one_cloud(
+            region_name='region2', argparse=None,
+            **base.USER_CONF['clouds']['_test_cloud_regions'])
+        # Not using assert_cloud_details because of cache settings which
+        # are not present without the file
+        self.assertIsInstance(cc, cloud_config.CloudConfig)
+        self.assertTrue(extras.safe_hasattr(cc, 'auth'))
+        self.assertIsInstance(cc.auth, dict)
+        self.assertIsNone(cc.cloud)
+        self.assertIn('username', cc.auth)
+        self.assertEqual('testuser', cc.auth['username'])
+        self.assertEqual('testpass', cc.auth['password'])
+        self.assertFalse(cc.config['image_api_use_tasks'])
+        self.assertTrue('project_name' in cc.auth or 'project_id' in cc.auth)
+        if 'project_name' in cc.auth:
+            self.assertEqual('testproject', cc.auth['project_name'])
+        elif 'project_id' in cc.auth:
+            self.assertEqual('testproject', cc.auth['project_id'])
+        self.assertEqual(cc.region_name, 'region2')
+
     def test_fix_env_args(self):
         c = config.OpenStackConfig(config_files=[self.cloud_yaml],
                                    vendor_files=[self.vendor_yaml])

releasenotes/notes/load-yaml-3177efca78e5c67a.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - Added a flag, 'load_yaml_config' that defaults to True.
+    If set to false, no clouds.yaml files will be loaded. This
+    is beneficial if os-client-config wants to be used inside of
+    a service where end-user clouds.yaml files would  make things
+    more confusing.